MISCELLANEOUS CROPS. 135 



sembling the fluted sugar-loaves of the grocers' windows. 

 After the eggs have remained on the leaves for a few 

 days, the little caterpillars break out of them and proceed 

 to their work of destruction upon the tender leaves of the 

 cabbage. They eat voraciously, soon piercing the paren- 

 chyma of the leaves with a thousand holes, and often 

 completely destroying nearly the whole crop of oleraceous 

 plants (cabbages, broccoli, cauliflowers) ; and rendering 

 the plants disgusting by the quantity of their excrements " 

 (Dallas). The hairy caterpillars are more or less green 

 or yellow, with black spots (]?ig. 46 B). They are pro- 

 vided with mouths well adapted for masticating or chew- 

 ing hard substances, hence the damage done to cabbages 

 and similar plants. The caterpillars change their skins 

 three times, when they retire to some quiet spot and there 

 turn to green-coloured pupse (Fig. 46 C). " The butterfly 

 comes out in about a fortnight from the midsummer brood 

 of chrysalids (pupse), but not till the following spring from 

 the chrysalids that form in the autumn." The perfect 

 insect or butterfly has four white wings. The mouth is 

 purely suctorial, and is provided with a spiral trunk fitted 

 for drinking up the juices of flowers. Fortunately for 

 farmers and market gardeners, there are two natural foes 

 of P. brassicce belonging to the Ichneumonidce. Both 

 Microgaster glameratus and Pteromalus brassicce lay 

 their eggs in the larvae and pupae respectively of P. bras- 

 sicce. The eggs of the former parasitic fly turn to small 

 larvae which feed " on the fat of their host, who, bad luck 

 to him, goes on eating faster than ever. Retribution, 

 however, must come in time, and when the cabbage-eater 

 should turn into a chrysalis, the parasitic guests are 

 thinking of changing too, so they burst through the skin 

 of their host, and leave him to perish." Pteromalus bras- 



